ABSTRACT
Coherent processes like CARS, SRS, or variants thereof probe the molecular polarization and the phase of this polarization is imprinted on the generated signal. e phase carries information about the –ow of energy; whether the driving eld is below or above the molecular resonance or non-resonant. When only the intensity of the signal is detected, the information contained in the phase is lost and resonant signals cannot be separated from the non-resonant part. In mixtures of several compounds, the resonant CARS signal of less abundant constituents may be overwhelmed by the non-resonant background, preventing detection of resonant molecules.
